A method for detecting straightness deviations and/deformations in a rotary kiln, the rotary drum of which features bearing rings spaced apart from one another in the axial direction and respectively supported on rollers, the outer surface area of the rotary drum, the bearing rings, involves scanning the rollers and/or the shafts of the rollers in a contactless fashion with the aid of at least one scanning device and obtaining three-dimensional position data regarding the scanned object(s), and evaluating three-dimensional position data with respect to the occurrence of a deviation of (a) the rotary kiln axis from a straight line, (b) the rotary drum from a cylindrical shape and/or (c) the rotational axes of the rollers from a line extending parallel to the rotary kiln axis. A device for detecting straightness deviations and/or deformations in a rotary kiln, at least one scanning device and a rotary kiln so equipped are provided.